A Novel Aflatoxin B₁ (AFB₁) Degrading Enzyme from Lactiplantibacillus plantarum CD2

Aflatoxin B₁ is a major contaminant in food and feeds; its cosmopolitan distribution exerts a severe threat to global health and the world economy. Secured mitigation by probiotic bacteria will ameliorate the toxicity and improve food and feed safety. This study screened 26 isolates from various samples in coumarin media, and probiotic characterization identified one potent probiotic strain. The CD2 isolates obtained from home-fermented curd identified as Lactiplantibacillus plantarum strain CD2 and its cell-free supernatant produce 57.63% of Aflatoxin B₁ (AFB₁) degradation in phosphate-buffered saline at 37 °C in 72 h. In comparison, live cells, heat-killed cells, and cell lysate of the isolate were found to be less effective than the cell-free supernatant. However, Proteinase K, SDS, and heat treatment on cell-free supernatant substantially reduced the degradative potential, and purification by gel exclusion chromatography improved the degrading potential from 44.43% to 57.63%.The molecular weight of the purified enzyme was identified as ≈ 62.4 kDa with optimum activity observed at pH 7.2, 37 °C, and after 72 h of incubation. Similarly, the metal ion Cu²⁺ improved the degradation efficiency by 1.04% compared to the control, while Mg²⁺ and Mn²⁺ showed no effect. In contrast, Zn²⁺ and Fe²⁺ inhibited the degradation by 9.92% and 15.30%, respectively. The Lpb. plantarum strain CD_2 can ease the toxicity of AFB₁-contaminated agricultural crops and make them safer for various level of uses.